The era of niche subreddits is over these days. Reddit started ignoring subscriptions and just pooling all posts together and suggesting things the algorithm thinks you are interested in regardless of subscriptions.

Old.reddit.com is the only way to get something useful, "new" reddit is slow, ad riddled and full of irrelevant and unwanted noise.

Discoverability of new subs used to be a bit of an issue, but people do cross-post.